<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .main {
            /* 设置display: flex; 的元素就是容器 */
            width: 600px;
            border: 1px solid red;
            /* overflow: hidden; */
            display: flex;
        }
        .main > div {
            /* 容器的 直系 子标签就是项目 */
            width: 100px;
            height: 100px;
            border: solid;
            /* display: inline-block; */
            /* float: left;*/
        }
    </style>
</head>
<body>
    <div class="main">
        <div>1</div>
        <div>
            <div>2</div>
            <div>2</div>
            <div>2</div>
        </div>
        <div>3</div>
    </div>
</body>
</html>